我有一個 python 程序，我想通過 http 與 C 程序通信。我在 python 中使用請求將一些 json 數(shù)據(jù)發(fā)送到 C 中的套接字。有時，python 會吐出“由對等方重置連接”錯誤，我無法弄清楚。當我收到這個錯誤時，除了請求的內(nèi)容之外的所有內(nèi)容都由 C 程序發(fā)送和接收。在我的應用程序中，我還從一個用 Go 編寫的客戶端發(fā)出請求。對于那個客戶端，我永遠不會收到這些錯誤，這就是為什么我認為我在請求庫中缺少一些配置或簡單的解決方案。為什么會發(fā)生這種情況，什么可以解決我的問題？這是一個簡單的例子；套接字的東西顯然是我不太熟悉的：C服務器：#include <stdio.h>#include <stdlib.h>#include <unistd.h>#include <sys/socket.h>#include <netinet/in.h>#define RECV_BUF_SIZE 1024int main(void){ struct sockaddr_in serv_addr, cli_addr; serv_addr.sin_family = AF_INET; serv_addr.sin_addr.s_addr = INADDR_ANY; serv_addr.sin_port = htons(8080); int option = 1; int socketfd = socket(AF_INET, SOCK_STREAM, 0); setsockopt(socketfd, SOL_SOCKET, SO_REUSEADDR, &option, sizeof(option)); if (socketfd < 0) { perror("failed to start socket"); exit(1); } if (bind(socketfd, (struct sockaddr*) &serv_addr, sizeof(serv_addr)) < 0) { perror("failed to bind"); exit(1); } if (listen(socketfd, 1000) != 0) { perror("listen error"); exit(1); } char buf[RECV_BUF_SIZE]; while (1) { int addrlen = sizeof(cli_addr); int clientfd = accept(socketfd, (struct sockaddr*) &cli_addr, &addrlen); if (clientfd < 0) { perror("accept error"); } else { int n_recv = recv(clientfd, buf, RECV_BUF_SIZE, 0); // print everything, character by character. char* tmp_buf = buf; while (n_recv--) printf("%c", *tmp_buf++); printf("\n\n****************************\n\n"); FILE* res = fdopen(clientfd, "w"); fprintf(res, "HTTP/1.1 200 OK\r\n\r\n"); fclose(res); shutdown(clientfd, SHUT_RDWR); close(clientfd); } }}Python 請求腳本：import requestsjson_data = { "hello": "thanks"}requests.post("http://localhost:8080", json=json_data)謝謝！
1 回答
喵喵時光機
TA貢獻1846條經(jīng)驗 獲得超7個贊
關于服務器與客戶端的通信，有幾個小問題，比如不正確的變量類型和缺乏錯誤檢查。
我在我的評論前面加上了>>'條件編譯'來展示我如何用建議的改進替換了 OPs 代碼的某些部分。
警告：由于服務器不知道從客戶端接收的預期字節(jié)數(shù)，因此答案不包括循環(huán)，試圖檢索客戶端預期的所有字節(jié)
char buf[ RECV_BUF_SIZE +1 ]; // >> +1 for string terminator
while (1)
{
// >> the third parameter is a 'socklen_t', not an 'int'
socklen_t addrlen = sizeof(cli_addr);
int clientfd =
accept(socketfd, (struct sockaddr*) &cli_addr, &addrlen);
if (clientfd < 0)
{
perror("accept error");
}
else
{
// >>recv() returns a `ssize_t`, not an `int`
ssize_t n_recv = recv(clientfd, buf, RECV_BUF_SIZE, 0);
#if 0
// >>this takes WAY too long, so the connection
// >>could timeout
// print everything, character by character.
char* tmp_buf = buf;
while (n_recv--) printf("%c", *tmp_buf++);
#else
if( n_recv < 0 )
{ // then an error occurred
perror( "recv failed" );
write( clientfd,
"receive error",
sizeof( "receive error" ) );
close( clientfd );
}
else if( n_recv == 0 )
{ // then client closed connection
printf( "%s\n",
"client closed connection" );
close( clientfd );
}
else
{ // some data received from client
buf[ n_recv ] = '\0'; // terminate string
printf( "%s\n", buf );
}
#endif
printf("\n\n****************************\n\n");
#if 0
FILE* res = fdopen(clientfd, "w");
fprintf(res, "HTTP/1.1 200 OK\r\n\r\n");
fclose(res);
shutdown(clientfd, SHUT_RDWR);
close(clientfd);
#else
ssize_t writeBytes;
if( (writeBytes =
write( clientfd,
"HTTP/1.1 200 OK\r\n\r\n",
strlen( "HTTP/1.1 200 OK\r\n\r\n" ) ) )
!= strlen( "HTTP/1.1 200 OK\r\n\r\n" ) )
{ // then incomplete write
printf( "%s\n",
"write didn't write all bytes to client" );
}
close( clientfd );
#endif
}
}
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編輯
跟隨關于服務器與客戶端的通信，有幾個小問題，比如不正確的變量類型和缺乏錯誤檢查。
我在我的評論前面加上了>>'條件編譯'來展示我如何用建議的改進替換了 OPs 代碼的某些部分。
警告：由于服務器不知道從客戶端接收的預期字節(jié)數(shù)，因此答案不包括循環(huán)，試圖檢索客戶端預期的所有字節(jié)
char buf[ RECV_BUF_SIZE +1 ]; // >> +1 for string terminator
while (1)
{
// >> the third parameter is a 'socklen_t', not an 'int'
socklen_t addrlen = sizeof(cli_addr);
int clientfd =
accept(socketfd, (struct sockaddr*) &cli_addr, &addrlen);
if (clientfd < 0)
{
perror("accept error");
}
else
{
// >>recv() returns a `ssize_t`, not an `int`
ssize_t n_recv = recv(clientfd, buf, RECV_BUF_SIZE, 0);
#if 0
// >>this takes WAY too long, so the connection
// >>could timeout
// print everything, character by character.
char* tmp_buf = buf;
while (n_recv--) printf("%c", *tmp_buf++);
#else
if( n_recv < 0 )
{ // then an error occurred
perror( "recv failed" );
write( clientfd,
"receive error",
sizeof( "receive error" ) );
close( clientfd );
}
else if( n_recv == 0 )
{ // then client closed connection
printf( "%s\n",
"client closed connection" );
close( clientfd );
}
else
{ // some data received from client
buf[ n_recv ] = '\0'; // terminate string
printf( "%s\n", buf );
}
#endif
printf("\n\n****************************\n\n");
#if 0
FILE* res = fdopen(clientfd, "w");
fprintf(res, "HTTP/1.1 200 OK\r\n\r\n");
fclose(res);
shutdown(clientfd, SHUT_RDWR);
close(clientfd);
#else
ssize_t writeBytes;
if( (writeBytes =
write( clientfd,
"HTTP/1.1 200 OK\r\n\r\n",
strlen( "HTTP/1.1 200 OK\r\n\r\n" ) ) )
!= strlen( "HTTP/1.1 200 OK\r\n\r\n" ) )
{ // then incomplete write
printf( "%s\n",
"write didn't write all bytes to client" );
}
close( clientfd );
#endif
}
}
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